全文获取类型
收费全文 | 12095篇 |
免费 | 2592篇 |
国内免费 | 3929篇 |
专业分类
化学 | 9173篇 |
晶体学 | 335篇 |
力学 | 918篇 |
综合类 | 307篇 |
数学 | 1736篇 |
物理学 | 6147篇 |
出版年
2024年 | 14篇 |
2023年 | 149篇 |
2022年 | 392篇 |
2021年 | 351篇 |
2020年 | 416篇 |
2019年 | 422篇 |
2018年 | 413篇 |
2017年 | 494篇 |
2016年 | 527篇 |
2015年 | 631篇 |
2014年 | 791篇 |
2013年 | 1029篇 |
2012年 | 1039篇 |
2011年 | 1089篇 |
2010年 | 988篇 |
2009年 | 1040篇 |
2008年 | 1092篇 |
2007年 | 985篇 |
2006年 | 1036篇 |
2005年 | 896篇 |
2004年 | 705篇 |
2003年 | 510篇 |
2002年 | 540篇 |
2001年 | 510篇 |
2000年 | 502篇 |
1999年 | 378篇 |
1998年 | 224篇 |
1997年 | 194篇 |
1996年 | 175篇 |
1995年 | 130篇 |
1994年 | 123篇 |
1993年 | 105篇 |
1992年 | 107篇 |
1991年 | 80篇 |
1990年 | 85篇 |
1989年 | 90篇 |
1988年 | 59篇 |
1987年 | 58篇 |
1986年 | 59篇 |
1985年 | 47篇 |
1984年 | 37篇 |
1983年 | 32篇 |
1982年 | 15篇 |
1981年 | 15篇 |
1980年 | 9篇 |
1979年 | 12篇 |
1978年 | 5篇 |
1975年 | 2篇 |
1957年 | 2篇 |
1936年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
DaXinSHI YaQingFENG ShunHeZHONG 《中国化学快报》2005,16(5):685-687
Photoinduced synthesis of CO2 and CH4 was investigated using a batch reaction system on several photoactive materials supported on silicon dioxide. Single semiconductor showed higher selectivity to C1 compounds. The production of C2-C3 oxygenates took place preferentially on composite semiconductor photocatalysts. In particular, it was found that acetone was the primary product over Cu/CdS-TiO2/SiO2. 相似文献
102.
103.
A Novel and Efficient Catalytic System for Aerobic Oxidative Coupling of 2-Naphthol Derivatives 总被引:2,自引:0,他引:2
LiCHEN JingBoLAN ZhiHuaMAO XiaoQiYU RuGangXIE 《中国化学快报》2004,15(8):903-906
The paper reported a novel and efficient aerobic oxidative coupling reaction of 2-naphthol derivatives catalyzed by CuCu (Ⅰ or Ⅱ)N-alkylimidazole complexes in excellent yields. The crystal structure of CuCu(Ⅱ)N-methylimidazole complex to be determined by X-Ray. 相似文献
104.
The supersymmetric WKB approximation of ring-shaped oscillator potential in r and θ dimensions with spherical polar coordinates
下载免费PDF全文
![点击此处可从《中国物理》网站下载免费的PDF全文](/ch/ext_images/free.gif)
According to calculation of the energy spectrum of ring-shape oscillator potential by using the supersymmetric WKB approximation, it is shown that the energy spectrum of some noncentral separable potentials can be exactly obtained in r and θ dimensions by above method. 相似文献
105.
106.
由于痕量元素在煤中的含量低微、检测困难,加之其原子量一般较大,可能的反应途径多,使得相关的反应机理研究难度极大。本文结合作者的研究成果,介绍了煤燃烧过程中痕量元素化学反应动力学的国内外研究进展,包括痕量元素化学动力学机理的建立;相关的典型实验、计算模拟及其实验验证、动力学机理模型的简化;痕量元素反应动力学机理的完善和发展,包括采用简单碰撞理论、活化络合物理论(亦称过渡态理论,或绝对反应速率理论)对痕量元素化学反应动力学机理的修正;最后指出煤燃烧过程中痕量元素动力学研究的若干方向是: (1)痕量元素反应动力学模型数据库的建立;(2)煤燃烧过程中,主量元素和次量元素的动力学机理的完善; (3)各痕量元素之间动力学研究的开展; (4)实际燃烧过程中痕量元素动力学行为的研究。 相似文献
107.
Jing Lin CHEN Gang Qiang YIN Zhong Ning CHEN* State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Fuzhou 《中国化学快报》2003,(5)
Great attention is currently paid to the synthesis of polynuclear transition metal complexes as well as their photochemical, photophysical, and electrochemical properties. The design of multicomponent systems capable of performing useful light- and/or redox-induced function is of special interest1. The oxo-centered carboxylate-bridge trinuclear ruthenium clusters have been investigated extensively during recent decades because they have remarkable electron-transfer properties, intense visibl… 相似文献
108.
HL-2A tokamak, the first tokamak with divertor in China, has been constructed and put into operation in 2002. The main parameters are R=1.65 m, a=0.4 m, BT=2.8 T, Ip = 0. 48 MA. The divertor of HL-2A is unique, because it is characterized with a large closed divertor chamber. The device has double divertor chamber, but now it is operating with lower single null configuration to study the physics of divertor for the next step design of a divertor. Supersonic molecular beam injection (SMBI) system with LN2 cooling trap was first installed and demonstrated on the HL-2A tokamak in 2004. The first results of SMBI into HL-2A plasma are to demonstrate the function of the HL-2A divertor and to observe the cold pulse propagation during multi-pulse SMBI on HL-2A Tokamak. 相似文献
109.
110.
Wenping Deng Gang Xu Lei Wan Anwen Liu Bo Gao Junhe Du Shuiming Hu Yang Chen 《Acta Physico》2008,24(8):1329-1334
Apparatus integrating a Fourier transform-infrared (FT-IR) spectrometer and a mid-infrared difference frequency generation (DFG) laser spectrometer was built for the study of the matrix isolation spectrum in solid molecular hydrogen. A 3-cm-long molecular hydrogen crystal was grown in a liquid-helium Dewar, and its infrared absorption spectrum in the 1-5 μm region was recorded to test the system. The W0(0) (ν=0←0, J=6←0) line around 2410 cm−1 of solid hydrogen was investigated with the DFG laser spectroscopy. High-resolution matrix isolation spectrum of CO2 co-deposited with hydrogen on a BaF2 cold plate at liquid-helium temperature was studied. 相似文献